HEAT EXCHANGING SYSTEM AND METHOD FOR A HEAT RECOVERY STEAM GENERATOR

摘要

Heat recovery steam generator comprises a casing, low-pressure evaporator coils, preheater booster coils upstream thereof and feedwater heater coils downstream thereof, a water-to-water heat exchanger having low and high temperature paths; a first conduit from the preheater to the high-temperature path, and a second conduit from the feedwater heater to the preheater. A conduit can extend from feedwater heater to low-pressure evaporator. A conduit can extend from the water-to-water heat exchanger to the feedwater heater. High-pressure economizer coils can be upstream of the preheater, with a conduit exiting the feedwater heater to the high-pressure economizer. Additional coils can be upstream of the high-pressure economizer. The feedwater heater can comprise first and second sections, or first, second and third sections; or more sections. The connections among the various components and sections can be near their upstream and downstream faces.

主权项

1. A heat recovery steam generator comprising:
a casing having an inlet and an outlet and a gas flow path there between for gas flow upstream from the inlet toward the outlet downstream therefrom; low pressure evaporator coils of heat exchanger tubes, the low pressure evaporator coils located within the casing downstream from the inlet; preheater booster coils of heat exchanger tubes, the preheater booster coils located within the casing downstream from the casing inlet and upstream of the low pressure evaporator coils, so that gas passing through the inlet can flow downstream to pass through the preheater booster coils, and gas passing through the preheater booster coils can flow downstream therefrom; feedwater heater coils of heat exchanger tubes, the feedwater heater coils located within the casing downstream from the low pressure evaporator coils so that gas passing through the low pressure evaporator coils can flow downstream from the low pressure evaporator coils to pass through the feedwater heater coils; a water to water heat exchanger having a low temperature path and a higher temperature path; a first conduit extending from flow connection with the preheater booster coils to flow connection with the high temperature path of the water to water heat exchanger, the first conduit configured for water to flow there through from the preheater booster coils to the water to water heat exchanger; and a second conduit extending from the feedwater heater coils to the preheater booster coils of heat exchanger tubes, the second conduit configured to allow water to flow there through from the feedwater heater coils to the preheater booster coils.